1. Field of the Invention
The invention relates to a method for plasma treatment of the surface of substrates by ion bombardment wherein a plasma of a supplied gas is generated and wherein the ions are accelerated by an electric potential onto the substrate. Moreover, the invention relates to a device for performing the method, comprising a vacuum chamber as well as comprising a gas supply.
2. Description of the Related Art
A first field of application of the method according to the invention as well as of the corresponding device is the manufacture of extremely thin wafers which are more and more in demand. Their advantages lie in the excellent heat dissipation of an integrated circuit (IC) as well as material savings for the chip card industry. With the currently known ion etching methods, however, only those chips can be produced which are relatively thick and therefore can easily break when they are integrated, for example, into a banking card.
The basic principle of ion etching methods resides in that a plasma of a supplied etching gas is generated. By connecting the substrate to be treated to a negative voltage potential, the ions are accelerated onto the substrate and erode the surface of the substrate in this way. In the known methods, the plasma is generated by high frequency introduction into the etching gas or by a microwave coupling system or in another comparable way. However, the ionization rate resulting from these methods for generating the plasma is relatively minimal and, correspondingly, the efficiency of the method for reducing the thickness of substrates by ion etching is unsatisfactory.
Nevertheless, the method upon which the invention is based is also suitable for and useable with other substrates, for example, according to a further field of application, for plasma activation of the surfaces of substrates which are plastic bodies, in particular, films. This plasma activation of the surface provides the basis for applying a bonding agent.